seahawks plan for a big party here at pier 39 on saturday. some of them told us they're worried about the potential for violence at candlestick park on sunday. >> second and 7. >> reporter: for football fans, it may be the hottest game of the season. sunday's battle between the 49ers and the seattle seahawks even has australian out of towners gearing up for the west coast rivalry. >> home support should be a win. >> i basically have to say it's a hostile environment. >> reporter: seahawks supporters are speaking about their safety in the wake of previous brawls there. in 2012 season, 55 ejections, 14 felony arrests. >> i've been getting quite a few emails were day saying my son's going to the game. should he wear his jersey or i'm bringing my girlfriend. am i going to be safe? >> reporter: for its part the 49ers put together a home field manual instructing their fans how to cheer and dress the part. also suiting up on sunday, san francisco police officers. >> this is undercover uniform of the day, at candlestick park. >> reporter: the police